/*
 * Copyright (C) 2004 NNL Technology AB
 * Visit www.infonode.net for information about InfoNode(R) 
 * products and how to contact NNL Technology AB.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, 
 * MA 02111-1307, USA.
 */

// $Id: FocusManager.java,v 1.13 2007/01/28 19:00:30 jesper Exp $
package com.supermap.desktop.ui.docking;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.util.ArrayList;

/**
 * @author $Author: jesper $
 * @version $Revision: 1.13 $
 */
class FocusManager {
	private static final FocusManager INSTANCE = new FocusManager();

	private int ignoreFocusChanges;
	private Timer focusTimer = new Timer(20, new ActionListener() {
		@Override
		public void actionPerformed(ActionEvent e) {
			updateFocus();
			focusUpdateTriggered = false;
		}
	});
	private boolean focusUpdateTriggered;
	private ArrayList lastFocusedWindows = new ArrayList();
	private Component focusedComponent;
	private PropertyChangeListener focusListener = new PropertyChangeListener() {
		@Override
		public void propertyChange(PropertyChangeEvent evt) {
			abstractFocusListener();
		}

	};

	private void abstractFocusListener() {
		if (ignoreFocusChanges > 0)
			return;

		ignoreFocusChanges++;

		try {
			triggerFocusUpdate();
		} finally {
			ignoreFocusChanges--;
		}
	}

	private void triggerFocusUpdate() {
		if (focusUpdateTriggered)
			return;

		focusUpdateTriggered = true;
		focusTimer.setRepeats(false);
		focusTimer.start();
	}

	private FocusManager() {
		KeyboardFocusManager.getCurrentKeyboardFocusManager().addPropertyChangeListener("focusOwner", focusListener);
		updateFocus();
	}

	static FocusManager getInstance() {
		return INSTANCE;
	}

	private void updateFocus() {
		focusedComponent = KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
		ArrayList oldFocusedWindows = lastFocusedWindows;
		lastFocusedWindows = new ArrayList();
		updateWindows(focusedComponent, focusedComponent, oldFocusedWindows);

		for (int i = 0; i < oldFocusedWindows.size(); i++) {
			RootWindow w = (RootWindow) ((Reference) oldFocusedWindows.get(i)).get();

			if (w != null)
				w.setFocusedView(null);
		}

	}

	void pinFocus(Runnable runnable) {
		ignoreFocusChanges++;
		final Component c = focusedComponent;

		try {
			runnable.run();
		} finally {
			if (--ignoreFocusChanges == 0 && c != null) {
				c.requestFocusInWindow();

				SwingUtilities.invokeLater(new Runnable() {
					@Override
					public void run() {
						SwingUtilities.invokeLater(new Runnable() {
							@Override
							public void run() {
								c.requestFocusInWindow();
							}
						});
					}
				});
			}
		}
	}

	void startIgnoreFocusChanges() {
		ignoreFocusChanges++;
	}

	void stopIgnoreFocusChanges() {
		if (--ignoreFocusChanges == 0) {
			updateFocus();
		}
	}

	static void focusWindow(final DockingWindow window) {
		if (window == null)
			return;

		window.restoreFocus();

		SwingUtilities.invokeLater(new Runnable() {
			@Override
			public void run() {
				SwingUtilities.invokeLater(new Runnable() {
					@Override
					public void run() {
						window.restoreFocus();
					}
				});
			}
		});
	}

	private static View getViewContaining(Component component) {
		return component == null ? null : component instanceof View ? (View) component : getViewContaining(component.getParent());
	}

	private void updateWindows(Component focusedComponent, Component component, ArrayList oldFocusedWindows) {
		Component componentTemp = component;

		while (true) {
			View view = getViewContaining(componentTemp);

			if (view == null)
				break;

			view.setLastFocusedComponent(focusedComponent);
			RootWindow rw = view.getRootWindow();

			if (rw == null)
				break;

			rw.setFocusedView(view);
			lastFocusedWindows.add(new WeakReference(rw));
			componentTemp = rw;

			for (int i = 0; i < oldFocusedWindows.size(); i++) {
				if (((Reference) oldFocusedWindows.get(i)).get() == componentTemp)
					oldFocusedWindows.remove(i);
			}
		}
	}

}
